Maxillary arch dimensional changes in the extraction and non extraction orthodontic treatment

الملخص EN

Aims:To investigate whether extraction status and gender had any significant influence on the maxillary arch dimensions.

Materials and Methods: A sample of 40 orthodontic patients (20 extraction and 20 non extraction) were included in this study.

Males and females were evenly represented in both groups.

All patients were treated with fixed edgewise appliances.

Dental casts were taken before and after final orthodontic treatment, fifteen maxillary arch parameters were evaluated at pre – and post – treatment stage and included; dental arch width at the canine, 1st premolar, 2nd premolar, 1st molar (at mesiobuccal and distobuccal cusp tips), arch depth at canine and 1st molar, arch lengths (incisal canine length, canine molar length and incisal molar length ), and arch perimeter.

A paired sample t– test was used to evaluate the treatment changes in the extraction and non extraction groups and also to compare between males and females before treatment and after treatment.

Results: Generally, in both genders, most pretreatment arch dimensions were not significantly different between extraction and non extraction groups, while after treatment the extraction treatment resulted in the reduction in the arch perimeters, arch depth, and arch length.

Where as the non extraction group showed a significant increase in most maxillary arch dimensions.

In addition both the extraction and non extraction treatment did not cause narrowing of the dental arch at the canine region.

The direction of post treatment changes were similar in male and female subjects.

However, the magnitude of the post treatment changes in some parameters differed significantly between females and males particularly in the non extraction group.

Conclusions: the extraction and non extraction groups showed similar trend in some maxillary dimensions and different in other dimensions, thus it was concluded that the kind of treatment may affect the maxillary arch dimensions.

In addition the non extraction group had a larger number of significant gender differences between females and males than the extraction group.